Cushioning-tire



R.- M. CLARK.

CUSHIONING' TIRE.

APPLICATION FILED res. 19. 1920.

Pat ent-ed Feb. 22,1921.-

3 SHEETSSHEET l- R. M. CLARK.

CUSHl0N?-G TIRE.

APPLICATION FILEi. FEB= 19, 1920.

1,369,728, Patented Feb 22,1921.

17 ven Z'or 7T; *1 C/Mf W Wig,

R. M. CLARK.

CUSHIONI NGII RE. APPLICATION FILED FEB- 19 I920.

22, 1921. 3 SHEETS -SHEET 3- Patented Feb l ly 6.

Wyl

UNITED ST'TS P TE W1V RoswnLr. 1a, CLARK, or CHICAGO; I'Lmnois.

- cUsHIoNING-aimn messes.

To all whom it may concern V 1 Be it knownthat I, RoswELL M. CLARK, a

citizen ot the United States,,residing at Chicago, llllDOlS, haveinvented-certainnew,

and useful Improvements in Cushioning- T1388; and 1 do hereby declarethe tollowing to beai'ull, clear, and exact description of theinvention, such as will enable others.

skilled in the art to which it appertains to make and use the same.

My invention relates to resilient wheels and moreparticularlyto'cushioning tires,

one of its general objects being that of pro viding as the maincushioning element a coiled vspring which has its turns so shaped as toutilize the resiliency thereof to an un usual extent and through anunusually large 7 portion of each rotation of the wheel. With this inview, niy-invcntion'ainis to provide a coiled spring for vehicletircs'in which each turn willafiord resiliency-not only through acontraction and a generally d sa wheel. Still another object oiinyinvention isthat or providing a single'coiled spring which may readilybe'inserted into the ordinary outer casingof a-tire in place of apneumatic inner tube, and in Whichthe convolutions of the spring Wlllautomatically be held by the outer tube from rotat ng-about theirsometimes included an endless coiled spring,

but the resulting resilien'cy has 'beenfound I very limited,ow1ng to theact that each.

turn of the coiled spring 'was' disposed in" a plane approximatelyiradial'ofxthe axis of the wlieeh so that theavailable resiliency wasonly that atlorded'by flexing each turn out 0t its normal circular form"into a laterallywidened oval -orrelliptica'l form. Cons'e- V quen'tly,in employing spring Wire of such a diameter as to avoid a permanent set,thee-dvisableextent of compression-oi each turn ra-- dially of the wheelhas been quite limited;

As'the result,'onlyirelatively "few turns of the ,;coil would have an 1operativekbearing at-any Application filed February 19 1920. Serial No.359,966

Cushioningtires {as heretofore built have Spccificationof Iietters'Fatent. Patented FiQ b; 22,1921:

one time, so that the cushioning aii'ordedbyj such a spring Waslimitedto that of avery small part of, the spring. Attemptshalve' been made toovercome this serious short coming by employinga lighter gage of wirefor the spring, but these have been unsatisfactory both because of theready damag mg of the lighter spring by sudden-shocks,

' and; also because of'the' danger of overstraining the coil and therebyeither calls ing' some turn of it to snap or else iving one or'moreturnsapermanent set :when' coinpressedfi 7 Furthermore, the symmetricalcontounof the ordinary coiled spring conforms so uni;

ttorinly to the outer tire casing into' which it may be insertedtliatit'perni'its of 'a-c'on V siderable creeping of the spring in thetire, thereby resulting in friction as well as, wear. i

To overcome these'and other objections to coiled springs asheretoforeproposed for use in cushioningtires, my invention" aimsto-jproyide a coiled spring in which every turn is adapted to be'bent intwoarelatively transverse directions, so that the resiliency will beafforded partly bv expanding the turns laterally of the wheeljivhile*c0rrespondingly coi'nl'i'rcssing them radially ofthe wheel,andpartly by increasingtheexf tent to which each turn is bowed vwhen inthe size of eachturn radially of the wheel, this is added to the actionobtained .by compressing the turn "from an approximately I circular.section to an oval or elliptical sec- 1 tion; consequently, thecombination of these two. flexing movements permits of my obtaining amuch larger contraction of the loop radially of the wheel than wouldothervie.wed from theside of the wheel; Since a this bowing action alsoimplies a reduction.

Wise be possible with the same diameter and grade of resilient wire.'Furthern1j0re,-by initially givingeach turn ofthe coil l suchv a formthat each lateral-half of it will appear to bedecidedly bowedior arcuatewhen VlQWVGd'fiOfil'ODG side of the Wheel,'-I employ a greater length ofwire in each turn and can therefore utilize the resiliencyjof the,

greater length. V f p I By thus-increasingthe available resiliency aswell-as the extent to hich each turn. of

the coil is contracted-and expanded radi-' ally ofthe Wheel during thenormal action,

I am able to distribute the pressure over a much: larger portioni 'ofthe fci reumiter-1 ence of the :Wheel than was ipossibletwith coil insuch a manner as to have at least one fairly well defined bending pointwhen viewed from "the side. of the, turn, and prelierably. so as tohavetwo such bending points disposed not far from the portions of theturn which are radially inwardand radially outward of the wheel. That isto say, I desirably provide the radially inward part of each turn with arelatively pointed tip portion which, when viewed from the side of thecoil, departs at an angle from'the main bowed or arcuate part of theturn from a'given point-onr By so doing, I providea innertip formationvfor each turn which; is adapted to bend somewhatindependently of therest of the turn inthe said bowing direc-' tion, and which is adapted tobear substantially flatwise for its entire length on the adjacent rim.portionof the wheel. I

1 Then I likewise provide a similar and even somewhat longer. tip forthat portion of each i thereby affording-two tip portions which are themain portion of the coil in the direction wheel to project between theclencher forma- Fig. 8 is a diagrammatic view showing one arrangement ofa mandrel used for Winding the spring coil of the preceding figures.

In manufacturing the spring coil which forms one of the'main parts of myinvention, I initially wind the coil on a mandrel seas to form astraight spiral ofthe desired length, then bend the resulting coil intoa ring form, and weld the free ends to each other. For winding the coil,the mandrel used may bearranged as shown diagrammatically in sideelevation in Fig. 8, in which turn which is radially outward of thewheel,

adapted to flex somewhat differently from tip portions which areradially inward of the tions on the outer tire casing, so that theseelements can cooperate in preventing each.

turn of the spring from rotating aboutits axis, thereby preventing thespring from beng twisted out of the position in which it is mosteffective in operation.

Still further objects will appear panying drawings, in which-- Figure 11s an elevat1on of awheel embodying my invention, with portions broken1' away to show the arrangement of the inner sleeve and of the springcoil. I

--Fig. 2iis an enlarged transverse section throng-lithe upper portion ofthe wheel, showing the mounting of the cushioning eleinents. I

Fig. his an enlarged side elevation of a from the i'ollowlngspecification and from the accomportion of the" wire spring coil whennot under compress on. a r Y lig. disa plan view of the same. V a I 11g. 0 1s a view-showing the coiled spring inclosed in a sleeve or lnnercasing, as it appears when it is being snapped into, or taken out of,the outer casing.

v I? 1g. 6 s a side view, of a single turn of the coiled spring. showingthe same both in its GlHXGQ position and as it appears when undercompression. V I 1g. 1 IS a View of a single turn taken at right anglesto Fig. 6, showing the same both relaxed and under compression.

figure the mandrel includes a cylinder having a series of projectingpins arranged in rows extending longitudinally otthe cylinder and withthe pins in each row uniformly spaced. In this case, the row 01 pins 1which are to define the outwardly directed tip ends are desirably alonga line diametrically OPPOSIEG to the line of pins 2 which define thebendsot' the coil that are to be directed radially lnward oi the wheel.l-Iowever, the

pins 2 are not in direct transverse alinement with thepins 1 but arelocated at the halfway points, as shown in Fig. 8 so that thecorresponding hall": of theturnat the rear of the mandrel will in eachcase lead to thenext pin 1. Projecting from the mandrel later ally, or.at right anglesto the linesof the pins 1 and 2, is a third row of pins3, which the rear of the mandrel the wire of each turn passes over pinscorresponding to the pins 5, 3 and 4. but positioneda little farther tothe right in F ig.18, so that the end of the turn which began at theleft} hand of pin 1 ends at the second of these pinsl. I

When thewireis thus wound, 'itwill be obvious from Fig. 8 that each'halfof each turn is substantially arcuate. in side elevation and that eachturn consists ofarelatively pointed forward bend A,'-a somewhat lesspointed inner bend B, and a pairof much longer and much less acute bendportions' (1' respectively. connectingthe bends A and B. lThecompleted'springcoilfi is desirably inclosed in. an inner tubeorprotective casing 7 -which is tightened about the spring coil by alacing 8 at the edge of the coil facing the axis of the wheel, or adja-Likewise, the portion of the wire cent tothe', shorter'bend portions Bof the I individual turns. Then the incased coil is slipped into anouter casing. or tread mom her 9 which desirably has a thickened treadportion and .also desirably has 'loutwar'dly V flattened, as shownsomewhat exaggerated 10in Fig. 7. Consequently, the clamping .of.

directed base flanges 10 adapted to engage clencher hook formations 11on'. a 'demountable rim, as for example after the manner shown in Fig.2. When thus incased, itwill be obvious from the above descriptionof themanner of forming the coils, that the two wire portions forming each ofthe said portions C of'a single turn will be somewhat the baseformations 10 between the clencher rim parts 11 will. cause the outer 1casing 9 to bear tightly against the somewhat flattenedi side portionsof the coil, thus preventing any portion of the coil from .rot-at.-

ingabout its axis. This prevention of rotationis'further aided by thepointing of the tip portions of each turn, as also shown 7 in Fig. 7, sothat the entire coil can readlly be maintained in predetermined positionWithout employing any auxiliary fasteuing devices and without using anydriving vdogs or the like in contact with the turns of the coil. Itherefore not only avoid thepossibility of having any partof'the coiltwis't outof line butalso grip it with a firmness adequate for keepingthe coil from creeping circumferentially of the wheel, but without 1with which they are in contact.

cmploying any metal parts engaging the,

coils, which is quite important, as metal parts thus disposed will beapt to crystal lize and weaken/the parts'of' the spring WV hen thewheelis thus assembled, the

outer casing 9 forms the tread member and also distributes some of thepressure over the various turns of the coil, being able to do thiswithout shifting the position. of the bend tips of the turnswitlilrespec't to the.

casing, so that Iavoid'any friction. or heatingwhich would be causedsuch shifting.

To understand theaction'of the spring as thus.constructed 'it. shouldfirst be noted from Fig. 3 that the outer bends A of successive turnsoverlap each other and that the same is true of theinner bend portionsB.

' Moreover, each of the outer bend portions A projects circumferentiallyof thewheel beyond portions of several adjacent turns, and when thespring is not under compression, all of the bends A and B are disposedoblique with respect to the radii of the wheel compressed, partlybylaterally distending the coil as shown in Fig. 7 and partly byapproaching the tip bends and B toward each other.. doing so,- theextreme portion Dmoves farther from the linejoining the tip bendsA andB, while these tip bends swing intopositions at right angles 'toa radiusof the wheel through them,

thus affording substantially fiatbearings for this portion of the coiledspring. 7 Thesebearing, portions may remain in their flat engagingpositions while the portion C of the spring between them bends stillfarther, and I can therefore obtain the relatively long elfectivebearingshowninFig. 1, so as to utilize the resiliency of'a much larger numberof turnsfth an is possible with the nary winding of spring coils. IFurthermore, the increased resiliency ordiwhich I secure by thisarrangement enables me to bendthe completed endless coil into curveshaving a much smaller radius than the normal radiusof the co l.Consequently,

the completed spring, even when incasedin a jacket, can be handledaftertheman'ner of, Fig. 5 for inserting it, in the outer fcasing or forremoving it if desired. By making the'inwardly directedbe nds B shorterthan the outwardly directed bends A; of the-coils,"

I. can readily compensate forvthe -diiferences in the circumferencesadjacent to these parts of the "coil, thus permitting me touse a ratherclose winding of the turns without having these engage." one? anotherduring their normalflexing. ."I-Iowev e'r, while I have described aparticular method of'winding the needed spring and: have illustrated myinvention, as employed with, a. certain form of demountable rim,- I'donot wish to be limited to vtheseor othendetails .ofthe "construc- V tionand arrangement here disclosed, it being,

obvious thatthe same mightybe modified in many-wa s without departing,from i the spiritef; the appended claims I claim as my invention 1', Ina cushioning tire, an endless: coiled spring havingeach lateral halfofevery" turn thereof substantially arcuate in side elevation.

2. In a cushioning tire, an endless coiled spring having each lateralhalf of every turn thereof substantially arcuate in .side'elevation, andhaving relativelysharp curvatures in each turn at the points thereofwhich are nearest to and farthest from the axis of the tire. 5 i

3. In a cushioning tire, an endless coiled spring having each lateralhalf of every turnthereof substantially arcuate in side ele-.

vation and having an appreciable angularity in theside elevationbetweeneach end' por tion of such half turn and main portion thereof.

spring having everyfiturn thereof substantially arcuate in the sideelevation of each lateral half thereof and having theturns so disposedthat a compression thereof radially the intermediary f 12 4:. In acushioning tire, an endless coiled V offthe the will both expand theturn lat-v erally and flex the turn to decrease the radius of thearcuate side'elevation.

- 55. In a Cushioning tire, an endless coiled spring having each lateralhalf of every turn substantially arcuate in side elevation and havingeach turn so disposed that pres sure on the same radially inward of thetire will bothexpand the turn laterally and'flex the turnto dispose theends of each lateral half turn'substantially parallel to each otherinside elevation. i

6.111 a cushioning tire, anendless coiled springhaving every turnsubstantially elliptical in contour and substantially arc'uate in y theside elevation of each lateral half thereof. v v

7. In a cushioning t1're,'an endless coiled spring having all of itsconvolutlons so arrangedthat the side elevation of the complet edispring will show the nearer half of each convolution substantiallyarcuate in contour" and bo'wed into. an adjacent, half convolution. V Iv 8. 'In a cushioning tire, an endless coiled spring having each turn sodisposed that the portionfarthest from the axis of the tire projectscircumferentially of the tire beyond the center portionsof a pluralityof adjacentturiis.v i 9'. In a cushioning tire, an endless coiled springhaving each turn somewhat flattened oblique to'the medial plane of therim, and an outer tire housing the sp'ring'and cooperating with the saidj. flattening of "the coils to prevent the coils from rotating about Itheir axes. V i I g s i v 10, ,A wheel rim having clencher' formations,an endless coiled sprlng surroundlng the 'medial portion thereof andhaving each turn thereof somewhat flattened obliquely to the medialplane of the rim, and a'treadcarrying casing housing the spring andhavingjlateral formations engaging the said clencher formations; thesaid formations on the casing and rim being so disposed as to cause thecasing to snugly house the spring,

whereby the said formations cooperatewith the flattening of the coils toprevent rotary movement of said coils about their axes.

11; A cushioning tire including an endless coiled spring having innerand outer portions' of each turn more oblique than the intermediateparts of the same turn, with fl 5 respect to aplane axial ofthe tire andpass-' ing through the center of the said turn.

' 12. A cushioning tire' including an endlesscoiled spring havingrelatively short inner and, outer-portions of each turn more obliquethan the, intermediate parts of the same turn.

13. A cushioning tire including an endless I 7 coiled spring havingrelatively short inner and outer portions of each turn more oblique thanthe intermediate parts of the same turn,

so turn, with respect to a plane axial ofithe'tire i and passing throughthe center of the said with respect toa plane axial of the tire and vpassingthrough the center ofothe said turn,

what flattened portions symmetrically dis-.

posedv with respect tothe medial plane of Q the spring so as to approacha rhomboidalform havinc said medial plane.

7 Signed at Chicago l ebruary 1920., 7

its more acute angles at' the s V ROSWELL M. CLARK; f

